Even though I don’t played LoL for long and my opinion may be not precisely enough to judge the community in Lol, but I can speak from my experience in Dota 2 or HoN and communitys in this games are similar toxic like Hots. So it’s easy to make the conclusion LoL is no different in general. Moba games have one thing in common they are team-based games and this already leads to toxicity. We know this also from Shooter games.
You’re probably biased towards LoL.